Safety release for push button switch



1965 J. P. ca. B ORNE SAFETY RELEASE FDR PUSH BUTTON SWITCH Filed Dec. 7, 1965 INVENTOR JEAN R G. HORNE AGE United States Patent 3,288,946 SAFETY RELEASE FOR PUSH BUTTON SWITCH Jean Paul Georges Borne, Paris, France, assignor to Labiratoires dElectronique et de Physique Appliquees Filed Dec. 7, 1965, Ser. No. 512,115 Claims priority, application France, Dec. 9, 1964, 998,025 2 Claims. (Cl. 200) The invention relates to apparatus having a compact arrangement of switches and associated push buttons and more particularly to a safety device for preventing actuation of more than one switch or push button at a time.

In known apparatus of the type to which the invention applies, it is difficult to tell which push button or switch is in operative position and which is not.

An object of the present invention is to provide a simple inexpensive solution to the above-stated problem.

According to this invention, a safety release key is provided which is operatively associated with a plurality of push buttons so that only one push button and its associated switch may be actuated at a time.

In order that the invention may be better understood one embodiment thereof will be described in more detail and by way of example only with reference to the accompanying drawings in which:

FIG. 1 is a plan view of a device according to the invention;

FIG. 2 is a section along the line IIII of FIG. 1;

FIG. 3 is a section along the line IIIIII of FIG. 1;

FIG. 4 is a section through the central release pushbutton.

As seen from the plan view of FIG. 1, four push buttons 1 are disposed radially about a central safety-release key 2. The top of the casing 7 of the device is closed by a cover plate 3.

In the sectional view of FIG. 2, the right-hand button seen in FIG. 1, is in its operative position, whereas the other three buttons are in their inoperative position. As seen in FIG. 2 the push buttons 1 are each pivotally supported on a shaft 4. The force necessary to operate the buttons 1 can be adjusted by means of small friction springs 5. Preferably manipulation of the central safetyrelease key 2 is facilitated by the provision of a spring 6, one end of which bears against the casing 7, whereas the other end of spring 6 is engaged in a cavity in the lower end 14 of a stem 8 associated with the safety-release 2. This end 14 of the safety-release key is provided with a pair of orthogonal longitudinal slots 15 each of which receives the lower end of one of the buttons 1. Movement of the stem 8 is guided by a sleeve member 9 the lower end of which serves as a stop when the stem 8 rises under the action of the spring 6. Downward movement of the stem 8 is limited by the member 10 which also serves as a guide for the spring 6.

The sectional view of FIG. 3 shows the association of a micro-switch 11 with a push button 1. Switches 11 (only one being shown) are secured to the cover 3 by way of any suitable intermediate member 12. The element 13 serves for securing the cover 3 on the casing 7.

In operation, when a button 1 is pressed with sufiicient force to overcome the effect of the friction spring 5, the said button rotates about its shaft 4 secured at one of its ends. The lug 16 forming an extremity of the button enters the associated slot 15 provided in the lower part 14 of the stem 8. In this position the upper face of the lug 16 is parallel to and abuts against the interior face 17 of stem 8, which face is perpendicular to the axis of the safety-release key.

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Movement of a button 1 into the operative position, operates the switch 11 by virtue of a lateral shoulder or other suitable means. When a first button 1 is in its operative position, it is impossible to close a second switch 11 by operating a second button 1 since the lug 16 of the operative button is occupying the cavity, defined by the slots 15, the lug of a second button 1 cannot therefore enter said cavity.

To close another switch 11 it is first necessary to release the operative switch 11 and for this purpose all that is necessary is to press the safety-release key 2; depression of key 2 against the action of the spring 6 imparts to the operative button 1 rotation about the shaft 4 in the opposite direction to that necessary to close a switch 11. The spring 5 holds the released button 1 in its inoperative position and displacement of the shoulder provided on the button 1 releases the switch 11. When pressure is no longer applied to depress safety-release key 2, the spring 6 restores it to its initial position.

As soon as the said cavity is cleared, it is possible to operate any one of the buttons 1 and associated switches 11.

Various modifications are possible in the above-described embodiment. For example the buttons 1 may terminate in a forked end adapted to embrace a solid cylindrical stem 8.

What I claim is:

1. A safety release for a plurality of radially arranged push buttons and associated switches comprising a housing member having a plurality of switches and an associated push button, journal means for rotatably mounting each said push button on said housing member in radially spaced relation, and movable control means connected with each said push button, said control means being centrally located with respect to each said push buttons; said control means comprising an axially movable member having an enlarged portion at one end, a plurality of axially and radially extending slots in said enlarged portion, said slots intersecting within said enlarged portion for defining an axial central cavity terminating in a surface, said surface engaging with each said push button in its actuated position for preventing effective actuation of successive ones of said push buttons, axial movement of said control means displacing an actuated push button to its non-actuated position, and means coupled with each said push button for holding said buttons in their actuated position.

2. A safety release according to claim 1 wherein each said push button comprises a member of uniform thickness and having a generally pie-shaped configuration, said journal means mounting said push button members for rotation about an axis adjacent the apex of said pie-shape and extending through said members in the direction of thickness, each said push button member also having a projection extending into one said slot whereby .upon actuation of one of said push buttons into its actuated position the associated projection engages said surface and obstructs said central cavity thus preventing actuation of another one of said push buttons.

References Cited by the Examiner UNITED STATES PATENTS 1,239,833 9/1917 Singer 200159 X 2,295,518 9/1942 Meuer 2005 X 2,607,875 8/1952 Sheidler.

ROBERT K. SCHAEFER, Primary Examiner.

I. R. SCOTT, Assistant Examiner. 

1. A SAFETY RELEASE FOR A PLURALITY OF RADIALLY ARRANGED PUSH BUTTONS AND ASSOCIATED SWITCHES COMPRISING A HOUSING MEMBER HAVING A PLURALITY OF SWITCHES AND AN ASSOCIATED PUSH BUTTON, JOURNAL MEANS FOR ROTATABLY MOUNTING EACH SAID PUSH BUTTON ON SAID HOUSING MEMBER IN RADIALLY SPACED RELATION, AND MOVABLE CONTROL MEANS CONNECTED WITH EACH SAID PUSH BUTTON, SAID CONTROL MEANS BEING CENTRALLY LOCATED WITH RESPECT TO EACH SAID PUSH BUTTONS; SAID CONTROL MEANS COMPRISING AN AXIALLY MOVABLE MEMBER HAVING AN ENLARGED PORTION AT ONE END, A PLURALITY OF AXIALLY AND RADIALLY EXTENDING SLOTS IN SAID ENLARGED PORTION, SAID SLOTS INTERSECTING WITHIN SAID ENLARGED PORFOR DEFINING AN AXIAL CENTRAL CAVITY TERMINATING IN A SURFACE, SAID SURFACE ENGAGING WITH EACH SAID PUSH BUTTON IN ITS ACTUATED POSITION FOR PREVENTING EFFECTIVE ACTUATION OF SUCCESSIVE ONES OF SAID PUSH BUTTONS, AXIAL MOVEMENT OF SAID CONTROL MEANS DISPLACING AN ACTUATED PUSH BUTTON TO ITS NON-ACTUATED POSITION, AND MEANS COUPLED WITH EACH SAID PUSH BUTTON FOR HOLDING SAID BUTTONS IN THEIR ACTUATED POSITION. 